The invention has been devised primarily for application to apparatus for raising and lowering a person, for use in caring for disabled, injured or infirm persons and for medical purposes, for example, for assisting a person to get into and out of a bath or up and down from and to the floor. Although the following description of the invention is directed mainly to this application of the invention, it is to be understood that there is no limitation in this regard as the invention is applicable to any appropriate type of apparatus for lifting and/or lowering persons or objects. Purely by way of example there may be mentioned apparatus for gaining access to elevated locations and apparatus for lifting and loading objects, for example lifting trolleys, lifting tables and pallet trunks.
According to the invention there is provided an apparatus for lifting or/and lowering persons or objects which comprises a structure provided with or adapted to be provided with a support for persons or/and objects, said structure having two parts which are movable relative to one another between an erected condition in which the support is in a raised position, and a collapsed condition in which the support is in a lowered position, and an inflatable means operatively connected between the parts of the structure so as to move said parts between the erected and collapsed conditions on inflation and deflation thereof.
Preferably the two parts of the structure are pivotally connected together. Preferably they are arranged in an X-configuration although other arrangements may be used, for example a number of pivoted links of any other appropriate configuration.
In a preferred embodiment of the invention the structure comprises two X-frames each comprising two members pivotally connected together at locations intermediate their ends, the two frames being disposed in planes parallel to one another and arranged, in use, to stand upright, the frames being connected together by one or more transverse members. However, other arrangements are possible within the scope of the invention, for example the structure may comprise only one such X-frame or three such X-frames disposed in spaced parallel relationship.
The inflatable means preferably comprises at least one inflatable bag extending between the two relatively movable parts of the structure.
Where the structure is of an X-configuration the bag is preferably formed with an opening and is arranged to surround the pivotal connection of the said two parts of the structure so that a portion of the bag lies between the two parts of the structure at one side of the pivotal connection and an opposed portion of the bag lies between the parts at the other side of the connection, whereby inflation and deflation of the bag, respectively, opens the structure in scissors-fashion and allows the structure to close in a similar fashion under the weight of a person or object on the support or just under the weight of the structure itself if there is no person or object on the support.
In the case of an apparatus having a single X-frame the bag will have only one, central opening but where the apparatus has two or more X-frames disposed in spaced parallel planes the bag may have a corresponding number of separate openings through which the respective frames extend or a single central opening containing all the frames. Thus, when there are separate openings the two opposed portions of the bag lying between the two relatively movable parts of the structure at opposite sides of the pivotal connection are connected together by a number of further portions of the bag which is one more than the number of openings in the bag.
The bag may be provided with tie means for connecting together the said two opposed portions of the bag at opposite sides of the or at least one opening in the bag. In the case of an apparatus having two or more X-frames in spaced parallel relationship, if the bag has only one central opening there may be just one such tie means extending across the opening, but if the bag has two or more openings a corresponding number of such tie means is preferably provided, one extending across each opening. The or each tie means may be two elongate elements connected to the respective portions of the bag and joined by a releasable connector which when released facilitates fitting of the bag to the structure and its removal. The tie means cause the bag to centre itself relative to the X-frames on inflation of the bag and prevent distortion of the bag which might otherwise cause an uneven application of forces by the bag to the parts of the structure on inflation of the bag and create strains in the structure of the bag.
The inflatable means may comprise a single bag or a number of bags.
In the case of an apparatus having a structure of X-configuration, for example one or more X-frames, the bags are preferably arranged in superimposed relationship. The bags may be arranged to be inflated and deflated simultaneously or one after the other.
The apparatus may further comprise means for producing a supply of compressed air, for example a pump or a compressed air cylinder, connected to the inflatable means and valve means for controlling the supply of air to the inflatable means and expulsion of air from the latter.
Alternatively the valve means may be connectible to an external source of compressed air.
The or each bag may be provided with internal or external restraint means adapted to limit the degree of permissible inflation of the bag and hence the height to which the support can be raised.
Where the structure is of X-configuration, one of the two parts thereof is preferably provided at its lower end with wheels, for example in the form of rollers or castors, arranged to run on a surface on which the apparatus is standing, towards and away from the lower end of the other part as the structure is moved between its erected and collapsed conditions, so that such movement takes place easily and smoothly. In this event, where the apparatus is to be used as a stationary apparatus, the lower end of said other part is preferably provided with means for preventing movement thereof relative to the said surface, for example non-slip feet or suction pads. Alternatively, where the apparatus may be required to be used to move persons or objects from place to place as well as lifting or/and lowering them, the lower end of said other part is preferably provided with wheels which may be equipped with braking means operable to prevent movement of the apparatus over the surface concerned on erection and collapsing of the structure.
The upper end of one of the parts of the structure may be provided with means for attachment to the support, and in this event the upper end of the other part is preferably provided with means adapted to permit it to slide or run along a lower surface of the support on erection and collapsing of the apparatus. These means may be sliders or wheels.
The support may simply comprise a platform of an appropriate size so that a person can sit and/or lie upon it. In other examples the support may be in the form of a seat or a stretcher which is detachable from the structure and which may also be combined with a platform, and for raising and lowering objects the support may likewise be a platform or of any other appropriate form such as a cradle or cage.
To enable the apparatus to lift and/or lower persons or objects to or from greater heights, it may be provided with one or more additional structures with inflatable means similar to the first structure and/or one or more additional structures similar to the first structure but without similar inflatable means, the structures being arranged one on top of the or each other so that they can be moved between their erected and collapsed conditions by movement of the said parts of the structure having inflatable means or of at least one of the structures having inflatable means between their erected and collapsed conditions under the control of said inflatable means, the structures being arranged one on top of the or each other. In the case of such an apparatus which has two or more structures with inflatable means, these inflatable means may be inflatable and deflatable together or independently.
Thus, where the structures comprise X-frames, the first structure may have pivotally connected to the upper ends of its frames the lower ends of the frames of a second structure, the upper ends of these frames either supporting the support or being similarly connected to a third structure which carries the support or is in turn similarly connected to one or more other such structures carrying the support.